In a number of industries, furniture being one of them, there has been and there is still a need for a time delay switch that is responsive to a physical act, such as pushing a piece of wood stock into a predetermined position to start a desired operation (a sawing or wood carving operation for example) and after a predetermined length of time (time for the operation to be finished) the sawing or wood carving mechanism is automatically de-energized and this de-energized state is maintained while the stock is withdrawn from the working area and the switch repositioned for a subsequent like operation. Only after another piece of stock is again inserted into the same predetermined position is the switch activated to repeat the operation. Accuracy and variability of the predetermined time of operation (or non-operation if desired) is highly desirable in such switch and the means that is used to fix and to change the "on" or "off" time interval should be reliable, rugged, easily adjustable and precise.
Repetitive actions, like that described above, require a switch that can be either stationary or mobile and one that can be "re-set" in preparation for a subsequent action after having been rendered to a predetermined state ("on" or "off") for a given time. Resetting must take place in response to the removal of the work stock from the place where it is being subjected to active work and while the switch itself is and is maintained in a predetermined (for example "off") state. It is towards the solution of these problems that the present invention is directed.